| 1901 February 20th | 1901 February 28th |
| Before appearance of Nova | The Nova |
NOVA PERSEI. Photographs by A. STANLEY WILLIAMS, Hove, Sussex. | |
Spectrum of Nova Persei. (F. Ellerman, 40 in. Yerkes.)
Now to put this theory to the proof. In the early morning of the 22d of February, 1901, Dr. Anderson, the discoverer of Nova Aurigæ, perceived that Algol had a neighbor, a star as bright as itself, which had never been there before. Within twenty-four hours of its detection the newcomer rivalled Capella, and shortly after took rank as the premier star of the northern hemisphere. Its spectrum on the 22d was found at Harvard College Observatory to be like that of Rigel, a continuous one crossed by some thirty faint dark lines. On the 24th, however, so soon as it began to wane, the bright lines of hydrogen were conspicuous with their dark correlatives, just as they had been with Nova Aurigæ and other novæ. At the same time each particular spectral line proved a law unto itself, some shifted more than others, thus negativing motion as their only cause and indicating change of pressure or density as concerned concomitants of the affair. Blue emissions like those of Wolf-Rayet stars next made their appearance; then a band, found by Wright at the Lick to characterize nebulæ, shone out, and finally in July the change to a nebular spectrum stood complete.
| THE MOVING NEBULA SURROUNDING NOVA PERSEI. | |
1901, September 20th. | 1901, November 13th. |
Drawn by G. W. RITCHEY, from Photographs taken with the 24-in. Reflector, YERKES OBSERVATORY. | |